I'm playing Guadalcana as allied. I have taken all of the bases that have large victory points. At this this time I'm just waiting for the game to end and give me my victory. Is there a way do this; forcing the game to end. If not does it stop at a date, or by victory points, or something?

There is no early end. If your playing the AI and it's gotten a butt kicking, then the game is essentially over. Winning the scenario as Japan is challenging enough for a human player given the logistical constraints and the historical piecemeal commitment of ground troops, the AI winning as Japan short of a stunning carrier victory early on is even more remote.